1 | // (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000. |
---|
2 | // Use, modification and distribution are subject to the Boost Software License, |
---|
3 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
---|
4 | // http://www.boost.org/LICENSE_1_0.txt). |
---|
5 | // |
---|
6 | // See http://www.boost.org/libs/utility for most recent version including documentation. |
---|
7 | // |
---|
8 | // Crippled version for crippled compilers: |
---|
9 | // see libs/utility/call_traits.htm |
---|
10 | // |
---|
11 | |
---|
12 | /* Release notes: |
---|
13 | 01st October 2000: |
---|
14 | Fixed call_traits on VC6, using "poor man's partial specialisation", |
---|
15 | using ideas taken from "Generative programming" by Krzysztof Czarnecki |
---|
16 | & Ulrich Eisenecker. |
---|
17 | */ |
---|
18 | |
---|
19 | #ifndef BOOST_OB_CALL_TRAITS_HPP |
---|
20 | #define BOOST_OB_CALL_TRAITS_HPP |
---|
21 | |
---|
22 | #ifndef BOOST_CONFIG_HPP |
---|
23 | #include <boost/config.hpp> |
---|
24 | #endif |
---|
25 | |
---|
26 | #ifndef BOOST_ARITHMETIC_TYPE_TRAITS_HPP |
---|
27 | #include <boost/type_traits/arithmetic_traits.hpp> |
---|
28 | #endif |
---|
29 | #ifndef BOOST_COMPOSITE_TYPE_TRAITS_HPP |
---|
30 | #include <boost/type_traits/composite_traits.hpp> |
---|
31 | #endif |
---|
32 | |
---|
33 | namespace boost{ |
---|
34 | |
---|
35 | #ifdef BOOST_MSVC6_MEMBER_TEMPLATES |
---|
36 | // |
---|
37 | // use member templates to emulate |
---|
38 | // partial specialisation: |
---|
39 | // |
---|
40 | namespace detail{ |
---|
41 | |
---|
42 | template <class T> |
---|
43 | struct standard_call_traits |
---|
44 | { |
---|
45 | typedef T value_type; |
---|
46 | typedef T& reference; |
---|
47 | typedef const T& const_reference; |
---|
48 | typedef const T& param_type; |
---|
49 | }; |
---|
50 | template <class T> |
---|
51 | struct simple_call_traits |
---|
52 | { |
---|
53 | typedef T value_type; |
---|
54 | typedef T& reference; |
---|
55 | typedef const T& const_reference; |
---|
56 | typedef const T param_type; |
---|
57 | }; |
---|
58 | template <class T> |
---|
59 | struct reference_call_traits |
---|
60 | { |
---|
61 | typedef T value_type; |
---|
62 | typedef T reference; |
---|
63 | typedef T const_reference; |
---|
64 | typedef T param_type; |
---|
65 | }; |
---|
66 | |
---|
67 | template <bool pointer, bool arithmetic, bool reference> |
---|
68 | struct call_traits_chooser |
---|
69 | { |
---|
70 | template <class T> |
---|
71 | struct rebind |
---|
72 | { |
---|
73 | typedef standard_call_traits<T> type; |
---|
74 | }; |
---|
75 | }; |
---|
76 | |
---|
77 | template <> |
---|
78 | struct call_traits_chooser<true, false, false> |
---|
79 | { |
---|
80 | template <class T> |
---|
81 | struct rebind |
---|
82 | { |
---|
83 | typedef simple_call_traits<T> type; |
---|
84 | }; |
---|
85 | }; |
---|
86 | |
---|
87 | template <> |
---|
88 | struct call_traits_chooser<false, false, true> |
---|
89 | { |
---|
90 | template <class T> |
---|
91 | struct rebind |
---|
92 | { |
---|
93 | typedef reference_call_traits<T> type; |
---|
94 | }; |
---|
95 | }; |
---|
96 | |
---|
97 | template <bool size_is_small> |
---|
98 | struct call_traits_sizeof_chooser2 |
---|
99 | { |
---|
100 | template <class T> |
---|
101 | struct small_rebind |
---|
102 | { |
---|
103 | typedef simple_call_traits<T> small_type; |
---|
104 | }; |
---|
105 | }; |
---|
106 | |
---|
107 | template<> |
---|
108 | struct call_traits_sizeof_chooser2<false> |
---|
109 | { |
---|
110 | template <class T> |
---|
111 | struct small_rebind |
---|
112 | { |
---|
113 | typedef standard_call_traits<T> small_type; |
---|
114 | }; |
---|
115 | }; |
---|
116 | |
---|
117 | template <> |
---|
118 | struct call_traits_chooser<false, true, false> |
---|
119 | { |
---|
120 | template <class T> |
---|
121 | struct rebind |
---|
122 | { |
---|
123 | enum { sizeof_choice = (sizeof(T) <= sizeof(void*)) }; |
---|
124 | typedef call_traits_sizeof_chooser2<(sizeof(T) <= sizeof(void*))> chooser; |
---|
125 | typedef typename chooser::template small_rebind<T> bound_type; |
---|
126 | typedef typename bound_type::small_type type; |
---|
127 | }; |
---|
128 | }; |
---|
129 | |
---|
130 | } // namespace detail |
---|
131 | template <typename T> |
---|
132 | struct call_traits |
---|
133 | { |
---|
134 | private: |
---|
135 | typedef detail::call_traits_chooser< |
---|
136 | ::boost::is_pointer<T>::value, |
---|
137 | ::boost::is_arithmetic<T>::value, |
---|
138 | ::boost::is_reference<T>::value |
---|
139 | > chooser; |
---|
140 | typedef typename chooser::template rebind<T> bound_type; |
---|
141 | typedef typename bound_type::type call_traits_type; |
---|
142 | public: |
---|
143 | typedef typename call_traits_type::value_type value_type; |
---|
144 | typedef typename call_traits_type::reference reference; |
---|
145 | typedef typename call_traits_type::const_reference const_reference; |
---|
146 | typedef typename call_traits_type::param_type param_type; |
---|
147 | }; |
---|
148 | |
---|
149 | #else |
---|
150 | // |
---|
151 | // sorry call_traits is completely non-functional |
---|
152 | // blame your broken compiler: |
---|
153 | // |
---|
154 | |
---|
155 | template <typename T> |
---|
156 | struct call_traits |
---|
157 | { |
---|
158 | typedef T value_type; |
---|
159 | typedef T& reference; |
---|
160 | typedef const T& const_reference; |
---|
161 | typedef const T& param_type; |
---|
162 | }; |
---|
163 | |
---|
164 | #endif // member templates |
---|
165 | |
---|
166 | } |
---|
167 | |
---|
168 | #endif // BOOST_OB_CALL_TRAITS_HPP |
---|